Currently there are 41 native Standard Prime lenses for Sony A9 III and 32 of these lenses are autofocus (AF) type.
A9 Mark III also has a sensor based image stabilization system which means that all of these lenses will be stabilized when used on A9 Mark III.
Since Sony A9 III has environmental sealings (Weather Sealing), you may like to couple your camera with one of these 21 Standard Prime lenses with Weather Sealings.